The structure stability of negative symptoms: longitudinal network analysis of the Brief Negative Symptom Scale in subjects with schizophrenia

Introduction Negative symptoms (NS) represent an unmet need of treatment in schizophrenia (SCZ). As a result, these symptoms pose a significant burden on patients, their families, and the health care system. In the last decade, the conceptualization model that has received the most support from the literature has described 2 domains of NS: the expressive deficit (EXP), which includes blunted affect and alogia, and the motivational deficit (MAP), which includes avolition, asociality, and anhedonia. However, different confirmatory factor-analytic studies suggest that the bi-dimensional model may not capture the complexity of this construct, which could be better defined by the 5-factor model. To date no study exploiting innovative tools and state of the art assessment instruments has yet been conducted to evaluate the NS structure stability over time. Objectives The aim of this study was to investigate the stability of the latent structure of NS in subjects with SCZ. Methods NS were assessed in 612 subjects with SCZ using the Brief Negative Symptom Scale (BNSS) at the baseline and after 4-year follow-up. A network invariance analysis was conducted for the data collected longitudinally. Results Results showed that the BNSS’ items aggregated to form 5 distinct domains (avolition, asociality, blunted affect, alogia and anhedonia). The result of the network invariance test indicated that the network structure remained unchanged over time (network invariance test = 0.13; p = 0.169) while its overall strength decreased significantly (6.28 baseline, 5.79 at follow-up; global strength invariance test = 0.48; p = 0.016). Conclusions The results of this study show how the construct of NS can be better explained by the 5 individual negative symptoms and that this model is almost stable over time. Therefore the 2-dimensional model may be insufficient to describe the characteristics of NS. This data is of important relevance with consequent implications in the study of pathophysiological mechanisms and the development of targeted treatments for NS. Disclosure of Interest None Declared

Introduction: There has been a continuous effort to discover and specify the neural correlates of schizophrenia (SCZ) based on spontaneous electroencephalogram (EEG) records. Besides contributing to a more effective diagnosis, biomarkers can be crucial to SCZ to hope for therapeutic progress. Objectives: a literature review was conducted to ascertain whether or not quantitative EEG spectral abnormalities are consistent enough to warrant additional effort towards developing them into a clinical diagnostic test for schizophrenia. Methods: A systematic search of the databases , ScienceDirect, and PubMed was conducted using the following words : schizophrenia, electroencephalography, neurobiology. The Preferred Items Reporting for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed in the construction of this literature review. Primary research articles that reported descriptive EEG results, included comparisons of subjects with and without antipsychotic therapy, and excluded patients with epilepsy were included in the analysis. We analyzed pooled data, where possible, from studies with a similar intervention and methodology. Results: Our study included 11 articles on quantitative EEG changes in schizophrenic patients divided as follows: 2 articles on the genetics of SCZ and EEG data, 3 articles on the psychopathology of SCZ and EEG data, 2 articles on hemispheric coherence, and finally 4 articles on the effect of treatment on EEG.Increased beta activity can be considered as an inherited feature of SCZ. Elevated delta/theta and gamma activity may serve as a specific biomarker for this condition. The delta wave may be a neurophysiological tool to differentiate between negative and positive forms of SCZ.EEG tracings of schizophrenic patients showed increased intra-and inter-hemispheric coherence compared to healthy subjects. Treatment with an antipsychotic drug was associated with a more marked increase in frequency bands in patients receiving an atypical antipsychotic drug. Conclusions: It is important to study the electroencephalographic changes not only to better understand the etiopathogenesis of SCZ, but also to search for specific physiological biomarkers.

EPP0269
The structure stability of negative symptoms: longitudinal network analysis of the Brief Negative Symptom Scale in subjects with schizophrenia E. Caporusso 1 *, G. M. Giordano 1 , A. Mucci 1 , P. Rucci 2 , F. Sanmarchi 2 , L. Giuliani 1 , A. Perrottelli 1 , P. Pezzella 1 , P. Bucci 1 , P. Rocca 3 , A. Rossi 4 , A. Bertolino 5 , S. Galderisi 1 and M. Maj 1 Introduction: Negative symptoms (NS) represent an unmet need of treatment in schizophrenia (SCZ). As a result, these symptoms pose a significant burden on patients, their families, and the health care system. In the last decade, the conceptualization model that has received the most support from the literature has described 2 domains of NS: the expressive deficit (EXP), which includes blunted affect and alogia, and the motivational deficit (MAP), which includes avolition, asociality, and anhedonia. However, different confirmatory factor-analytic studies suggest that the bi-dimensional model may not capture the complexity of this construct, which could be better defined by the 5-factor model. To date no study exploiting innovative tools and state of the art assessment instruments has yet been conducted to evaluate the NS structure stability over time.
Objectives: The aim of this study was to investigate the stability of the latent structure of NS in subjects with SCZ.
Methods: NS were assessed in 612 subjects with SCZ using the Brief Negative Symptom Scale (BNSS) at the baseline and after 4-year follow-up. A network invariance analysis was conducted for the data collected longitudinally. Results: Results showed that the BNSS' items aggregated to form 5 distinct domains (avolition, asociality, blunted affect, alogia and anhedonia). The result of the network invariance test indicated that the network structure remained unchanged over time (network invariance test = 0.13; p = 0.169) while its overall strength decreased significantly (6.28 baseline, 5.79 at follow-up; global strength invariance test = 0.48; p = 0.016).

Conclusions:
The results of this study show how the construct of NS can be better explained by the 5 individual negative symptoms and that this model is almost stable over time. Therefore the 2-dimensional model may be insufficient to describe the characteristics of NS. This data is of important relevance with consequent implications in the study of pathophysiological mechanisms and the development of targeted treatments for NS. Introduction: Understanding the psychological meanings of a rigorous protocol for introducing a drug to patients is a challenge of emotional management for clinical professionals. Clozapine is an effective drug for patients with schizophrenia resistant to treatment with first and second-generation antipsychotics. This medication has agranulocytosis as an important side effect. The medication protocol requires frequent blood draws to monitor any effect on blood cells. Investigating patients' emotional perceptions about the experience with this procedure was the triggering question of our study. Objectives: To interpret emotional/symbolic meanings attributed by patients with schizophrenia to the protocol of introduction of clozapine in follow-up at a specialized university service. Methods: Clinical-qualitative design of Turato. Semi-directed interviews with open-ended questions in-depth were conducted face-to-face with participants using clozapine. Closed sample by the theoretical information saturation criterion described by Fontanella. Data were treated by Faria-Schutzer's Clinical-Qualitative Content Analysis, employing psychodynamic concepts of the theoretical framework of Medical Psychology. Results: From the analysis of nine patients, three categories emerged: 1) "Anyway, I come here to stay alive": frequent blood collections of the protocol seem to have a good impact on patient's adherence to treatment; 2) To re-signify a psychiatric illness: the protocol reinforcing an embodiment of a medical diagnosis; 3) "It is a very big precaution": the protocol as real and emotional support to deal with the possibility of serious side effects. Conclusions: Although blood collection is a repetitive experience for patients, such a routine does not mean that the procedure brings symbolizations that are more charged than the disease itself. Patients can benefit from the commitment to attend blood collection frequently, as it removes them from possible social isolation, allowing social interaction; it brings the perception of emotional security due to the commitment to the clinical team. These benefits can lead the patient to develop new meanings for their life condition. Future qualitative research can be conducted to study the meanings of medical protocols in other diagnostic situations.